Artificial denture



Nov. 11, 1952 H. A. GODDARD 2,617,192

ARTIFICIAL DENTURE F'iled July 15, 1949 2 SHEETS-SHEET 1 INVENTOR. Huber? Axe/ands r oddard Nov. 11, 1952 H. A. GODDARD 2,617,192

ARTIFICIAL DENTURE Filed July 15, 1949 2. SHEETSSHEET 2 INVENTOR. Hubs Pf Axe /a/76/tl" addard F/a 7 Patented Nov. 11, 1952 UNITED STATES PATENT OFFICE ARTIFICIAL DENTURE Hubert Axelander Goddard, Knoxville, Tenn.

Application July 15, 1949, Serial No. 104,908

Claims. (Cl. 32--2) This invention relates to improvements in artificial dentures, and particularly to the occlusal or masticating surfaces of the upper and lower posterior teeth.

Heretofore, in the manufacture of artificial teeth, the cusps or chewing surfaces have been designed to follow, as closely as possible, natural teeth. Nature, in providing the human being with teeth, however, extended the process over a period of fifteen to twenty years, during which period teeth could shift and move from one place to another, so as to accommodate themselves to provide an occlusal surface for chewing, without interlocking or having maladjustments as to heighth of the teeth.

Artificial teeth, however, are placed in a more or less rigid material, and once being so attached to the plate material, shifting of th teeth is impossible. As a result of this practice, in a large percentage of dentures as now used, there are high spots, that is, places where the teeth, when the jaws are closed, produce an uneven and undesirable pressure which is transmitted to the mandible, causing sore spots and sensitiveness, which has a tendency to cause shrinkage of the tissues, resulting in a misfit of the denture.

Further, in artificial teeth as now manufactured, and in spite of the great care used in their fitting, the dentures are often found to lock in one or more directions, preventing easy mastication of food, distress to the wearer, and often dislodgment of on or more of the plates.

One object of this invention is to overcome the failures heretofore encountered in the use of artificial teeth, by providing masticating surfaces for the posterior teeth, which are in lateral alignment and so constructed with a valley and cutting cusps as to provide efficient masticating surfaces that will not lock, and which are so simple mechanically in design as to be easily set up in a denture plate with accuracy, and elimination of high spots.

These objects are best accomplished by forming the upper and lower posterior teeth with the surfaces in more or less complementary relations to each other, each of which teeth has a trough or valley formed laterally therein, the edges of the valleys forming more or less sharp cutting cusps, which teeth, when set in a denture, are arranged so that the inner or tongue side cusps of the upper teeth rest in the low point of the valley of the lower teeth, and the cheek side cusp of the lower teeth resting in the low point of the valley of the upper teeth, said valleys and cusps being arranged in alignment. It is not necessary that either the troughs or valleys or the cusps be continuous throughout the lower teeth, these being interrupted as they pass from tooth to tooth by the natural formation of the body of the teeth, but it is highly desirable, though not necessary, that each of the teeth, or at least a portion of each tooth carry the full profile of the valley and the peaks of the cusps.

A satisfactory and simple method of forming these surfaces is to arrange the teeth, the valleys and the cusps parallel to each other, in a direct line, or, where there is a marked bow in the mandible, it may be desirable to set the teeth in a suitable arc, with the troughs and cusps parallel and in alignment.

Several embodiments of this invention are illustrated generally in the accompanying drawings, in which:

Fig. 1 is a cross section of a pair of artificial dentures, showing the invention applied thereto;

Fig. 2 is a diagrammatic view of a pair of upper and lower teeth formed in accordance with this invention;

Fig. 3 is a top plan view of a series of upper teeth formed in accordance with this invention arranged in direct alignment; I

Fig. 4 is a similar view showing a series of the lower teeth;

Fig. 5 is a top plan view showing a horizontal row of teeth of modified construction;

Fig. 6 is a similar'view of a row of teeth in laterally curved alignment; and

Figs. 8, 9 and 10 are side elevation of pairs of teeth of modified construction.

The invention permits of a wide variety of applications and variations of the particular configurations of the valleys or troughs and the cusps.

Likewise, the outline of the occlusal surface in cross section need not be maintained in exact size throughout the entire teeth, but may be gradually enlarged from the rear to the front in some cases, but the cusps and valleys should be kept in alignment.

The invention is capable of being applied in many different forms of artificial dentures, such as plates, bridges, etc., which constitute the mounting or support for the teeth. These upper and lower mountings are shown generally in Fig. 1 and designated, respectively, at I and 2 adapted for holding the artificial teeth, which are shown therein and designated generally at 3 and 4, respectively. Each of the teeth 3 and 4, particularly of the posterior teeth such as the bicuspids and molars, has a chewing surface formed preferably with a concave trough bounded by ridges at opposite sides, one of the ridges on one tooth interfitting with the trough in the opposed tooth, as shown particularly in Figs. 1 and 2. I have illustrated diagrammatically in Fig. 2 one method by which the surfaces may be formed, which is described however merely a an example of this embodiment of the invention, subject to variations which may be made therein. This is particularly true of the proportions specified, which are given here merely as this example and not by way of limitation.

Take the greatest cross lateral dimension of the first lower molar 4 as a base and lay oiT the base diameter line ab. La oil a horizontl line c-d through the desired medin occlusion line of the teeth relative to the lower tooth. At a point in this median line 51/90 of the base diameter ab from the cheek side (at e) erect a perpendicular .line above the median occlusion line, and usin a point 1 in said perpendicular line 28/90 of said base diameter above the median occlusion line as a center, and with a radius of 83/180 of the base diameter (line fg) scribe a segment of a circle g-h 48 degrees on the cheek side of the perpendicular and 33 degrees on th tongue side of the perpendicular (gi). This segment of a circle will form the circular trough of the lower molar; the end h toward the check will form the peak of the lower high cusp, and the end 1' toward the tongue side will terminate at the inner edge of the sloping shelf hereafter described.

Draw a straight line through the terminal point h of the circular segment on the cheek side inclined outwardly and toward the base of the lower tooth, at an angle of 48 degrees to the said median occlusion line. This-inclined line (h -1i) will form the cheek side inclined surface of the lower tooth, the upper edge of which forms with that part of the circular surface, the ridge h of the cusp. Through the end of the circular are on the tongue side (i), and inclined outwardly and toward the base of the lower tooth, draw a line (ilc) inclined at 12 degrees to said median occlusion line. This line will form the small food shelf on the tongue side of the teeth. The two inclined planes, the 48 degree (IL-7') and the 12 degree (i-k), together with the concave surface of the circular arc (h-g-i), form the-profile of the masticating surface of each of the lower teeth, in cross section through the large molar.

Take the greatest cross lateral diameter of the first lower molar 4 as a base (ct-12). Lay off a horizontal line through the desired median occlusion line of the upper teeth (line .Z-m). At a point 11. in this median line of the base diameter from the cheek side erect a perpendicular line above the median occlusion line (outwardly from the tooth) and using a point in said perpendicular line of said base diameter above the median occlusion line as a center and with a radius 0-3) f i th of the base diameter scribe a segment of a circle (p-q) 48 degrees on the tongue side of the perpendicular and 33 degrees (p-r) on the cheek side of the perpendicular. This segment of a circle (p-q-r) will form the circular trough of the upper molar; the end q toward the tongue will form the peak of the large upper cusp, and the end 1' toward the cheek side will terminate at the edge of the natural tooth surface, and form the outer cusp.

Draw a straight line through the terminal q of the circular segment on the tongue side inclined outwardly and toward the base of the upper tooth and at an angle of 48 degrees to the said median occlusion line. This inclined line (qs) will form the tongue side inclined surface of the upper tooth, the lower edge of which forms with that part of the circular surface, the ridge of the large cusp. The ridge formed by the cheek side termination of the concave surface with the natural outer wall of the tooth forms the cheek side cusp of the upper teeth. The 48 degree plane (q-s) together with the concave surface of the circular arc (p-qr), form the profile of the masticating surfaces of the upper teeth, in cross section through the large molar.

As the molars and bicuspids are of different sizes, the bicuspids usually being smaller than the molars, in generating the masticating surfaces of the smaller teeth by moving the profile sideways and along the ridge of the upper or lower jaw, respectively, and parallel to the .occlusion line of the teeth, ridges of the cusps and other masticating surfaces may disappear and in nearly all cases are interrupted as they pass from one tooth to another. It is thebetter practice, as in forming the smaller teeth, to provide all teeth with a breadth and heighth of material to carry for a substantial portion of their length the entire concave circular surface and enough, of the 48 degree inclined plane to form the cusps.

In setting the teeth in dentures they are so arranged (whether straight line or curved with the jaw ridge) so that the lower high cusp (h), when the teeth are closed and centered, rests on the bottom of the concave surface or trough of the opposite tooth or teeth (at p), and the upper high cusp (q) rests on, the bottom (at g) of the concave surface or trough of the opposite lower tooth or teeth, the cusps resting 48 degrees of the arc of the concave surface apart; and the peak of the high cusps and the valleys of all teeth are in alignment, both lateral and vertical.

After thus determining the shape of the contact surfaces of the teeth, they may be so formed of any suitable or usual material for the purpose, with the same form of groove or trough and opposite ridges running lengthwise of the row of teeth as indicated generally in Figs. 3 and 4. The teeth may be located in the mountings l and 2 either on straight lines or on curved lines, but the troughs here designated at 5 are in direct longitudinal alignment with each other throughout the row of teeth at the corresponding side in which event the corresponding ridges 6 on opposite sides of the trough 5 are also substantially in longitudinal alignment. The teeth may be mounted on a slight arc extending along the curve of the mandible as in Fig. 6, or curved vertically as in Fig. '7. In some dentures it may be necessary to combine both. In any event, these troughs 5 still will be in longitudinal alignment along the corresponding arc, and the trough itself may be formed preferably on a slight arc. Four teeth are shown in each of Figs. 3 to '7, two of which are molars and the other two bicuspids, but in each instance they are formed preferably with the surfaces substantially as described above.

Fig. 5 is a plan view near the occlusal line of a set of teeth built with squared shoulders to provide more continuous cusps and valleys than in the more rounded conventional teeth shown in Figs. 3 and 4. In Fig. 5 the line tu and the line v--w are located approximately along the line of the peak of the cutting cusps.

of the application of this invention, wherein the upper teeth and lower teeth are shown at 89, |--H and l2l3 respectively and the cheek side of the teeth is shown at l4, l5 and I6 respectively.

When formed in the manner described, the teeth are more easily aligned in the mountings of the denture, and it is less tedious to obtain proper fit between the upper and lower teeth. At the same time better chewing action is obtained without attempting to imitate natural molars and bicuspids.

These teeth have been designed from a mechanical standpoint and not from a carving of natural teeth, but have been designed so that when masticating or chewing on either the right or left side the opposing teeth on the opposite side are in perfect and direct occlusion, thus preventing a raising or lowering of the dentures, eliminating the moving of the dentures that causes sensitive spots on the ridges and shrinkage of the gums and tissues and locking of the teeth.

As shrinkage takes place in the mouth. the lower denture under my construction cannot shift forward since the cutting surfaces of the teeth are wedge-shaped, the wedge being wider posterially and gradually becoming more narrow anterially, thus preventing a shifting forward of the mandible causing a protruding bite. These teeth can be set up on any curve or curves conforming to the mouth condyles.

They have a sharp cutting cusp, the upper opposing the lower lingually; in this method there is no locking cusp or cusp interference, making it possible for a lateral excursion rather than an open and closed bite or a chopping bite in mastication. This cutting cusp is very necessary for the protection of the ridges. A flat cusp or blunt-shaped cusp tends to cause an increase of the necessary amount of pressure applied in chewing, more than is necessary with the straight-lined cutting edged cusp on the teeth according to this invention.

These teeth are designed in such a way that they can be set up easily on any articulator. All that is necessary is that the trough and cutting edges be set in alignment, making it a very simple practice for the technician, and providing a very eficient masticating denture.

While the invention has been illustrated and particularly described in certain embodiments, it is recognized that other variations and changes may be made therein without departing from the invention, except as specified in the claims.

Iclaim:

1. In a denture, sets of upper and lower posterior teeth in opposed relation, each set of teeth including a plurality of teeth each having its masticating surface formed of a trough with the troughs of the teeth and said set substantially in longitudinal alignment with each other, and each set of teeth having ridges thereon forming cutting cusps extending substantially parallel with the troughs of the opposing teeth and intermediate the opposite sides thereof in opposed relation.

2. In a denture, sets of upper and lower posterior teeth in opposed relation, each set of teeth including a plurality of teeth each having its masticating surface formed of a trough with the troughs of the teeth of said set in longiutdinal straight alignment with each other, and each set of teeth having ridges thereon forming cutting cusps extending substantially parallel with the troughs of the opposing teeth and intermediate the opposite sides thereof in opposed relation.

3. In a denture, sets of upper and lower posterior teeth in opposed relation, each set of teeth including a plurality of teeth each having its masticating surface formed of a trough with the troughs of the teeth of said set in longitudinal curved alignment with each other, and each set of teeth having ridges thereon forming cutting cusps extending substantially parallel with the troughs of the opposing teeth and intermediate the opposite sides thereof in opposed relation.

4. In a denture, sets of upper and lower posterior teeth in opposed relation, each set including a plurality of teeth each having its masticating surfaces formed of a trough having ridges on opposite sides thereof, the troughs of each of said sets of teeth being in longitudinal alignment lengthwise of the mandible, and said ridges extending substantially parallel with the troughs and interfitting therewith in opposed relation.

5. In a denture, sets of upper and lower posterior teeth in opposed relation, each tooth having its masticating surfaces formed of a trough having ridges on opposite sides thereof, the troughs in the opposed teeth being laterally offset from each other with one ridge of each set of teeth interfitting in the trough of the opposed teeth, the troughs and ridges running substantially parallel to the marginal edges of the mandible, and the troughs in each set being in substantial alignment with each other.

6. In a denture, sets of upper and lower posterior teeth in opposed relation, each tooth having its masticating surface formed of a concave cylindrical trough having a ridge on each side thereof, the troughs in the opposed upper and lower teeth being laterally displaced but substantially parallel to each other and having the ridge of one tooth interfitting in the trough of the opposed tooth, and the troughs in each set being in substantial alignment with each other.

'7. In a denture, sets of upper and lower posterior teeth arranged in rows in opposed relation, each tooth having its masticating surface formed of a concave trough with ridges on opposite sides thereof, said troughs extending lengthwise of the row and in longitudinal alignment with the troughs in the other teeth of said row of teeth, each tooth being arranged with one of said ridges on one tooth intermediate the opposite sides of the trough of the opposed tooth in position for interfitting therein upon engagement of the teeth.

8. In a denture, set of upper and lower posterior teeth arranged in rows in opposed relation, each tooth having an occlusal contacting surface formed of a concave cylindrical trough extending lengthwise of the row and substantially in longitudinal alignment with the troughs in said row of teeth, each tooth having ridges on opposite sides of the trough, the upper and lower teeth being arranged with one of said ridges on one tooth intermediate the opposite sides of the trough of the opposed tooth in position for interfitting therein upon engagement of the teeth.

9. In a denture, upper and lower opposing artificial human teeth, each of said teeth comprising a body having a masticating surface formed of distinct ridges or cusps with an open valley or trough therebetween, the cusps and valleys extending substantially parallel with each other transversely of the teeth, the lingual cusp of the upper tooth being arranged to strike substantially in the center of the valley of the lower tooth, and the buccal cusp of the lower tooth being arranged to strike substantially in the center of the valley of the upper tooth, thereby providing two distinct cusp contacts between opposing teeth.

10. In a denture, upper and lower opposing artificial human teeth arranged in substantially parallel'rows, each of said teeth comprising a body having a masticating surface formed of distinct ridges of cusps with an open valley or trough therebetween, the cusps and valleys extending substantially parallel with each other transversely of the teeth and substantially parallel with the rows of teeth, the lingual cusp of the upper tooth being arranged to strike substantially in the center of the valley of the lower tooth, and the buccal cusp of the lower tooth being arranged to strike substantially in the center of the valley of the upper tooth, thereby providing two distinct cusp contacts between opposing teeth.

HUBERT AXELANDER GODDARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Gysi, Alfred-The Problem of Articulation, The Dental Cosmos, 1910, pp. 268-269. (Copy available in Div. 55.) 

